The proposed research has to do with the chemical modifications of the major allergenic protein of ragweed pollen antigen E. One aspect of the studies deals with the chemical degradation of antigen E into small peptide fragments. Some of the fragments were shown to suppres IgE antibody responses in antigen E primed mice and this suppression is at the T-cell level. This work will be continued so that the smallest fragments retaining the major T-cell determinants of antigen E can be identified and their structures established. Another aspect of the studies has to do with the preparation of conjugates of antigen E with mouse immunoglobulin G, with a synthetic copolymer of D-glutamic acid and D-lysine. Investigations will be made to establish the best procedures for the preparation of such conjugates with well-defined molecular compositions. The conjugates will be tested for their antigen-specific immunogenic activities in mice. Others have shown that hapten conjugates with the aforementioned carriers can suppress hapten specific IgE and IgG responses in mice. The proposed studies will test if the observations obtained with hapten-conjugates can be extended to conjugates of protein antigens. The proposed research is of significance in the treatment of immediate hypersensitivity in man, as the findings in the animal system can lead to more effective and less toxic reagents for immunotherapy in man.